Migration into Oregon is increasing as the economy improves, according to new population estimates from Portland State University.

The school's Population Research Center said this week that the state's population grew to 3,962,565 in 2014, a 1.1 percent increase from 2013.

The center said 74 percent of the increase is due to migration, while 26 percent is natural increase -- the number of births minus the number of deaths.

The numbers represent the population as of July 1 of each year.

Migration has increased as the economy improved, creating new employment opportunities in the state and leaving people in other parts of the country better position to take advantage of them, said Risa Proehl, the center's program manager.

"Even during the Great Recession, Oregon still saw net in-migration," she said. "It's been a trait for Oregon that as our economy improves, our net in-migration increases, so the situation isn't new."

More than half of the growth occurred in the Portland area, its share of the state's overall population has remained relatively steady.

Portland itself grew by 9,390 in 2014, while the cities of Bend, Salem, Beaverton, Eugene and Corvallis each saw their population grow by more than 1,000.

The Population Research Center estimates are, among other things, used to determine how state revenue should be disbursed. And the population growth has many implications for the economy, including potential effects on the labor pool and the housing supply.